A source or citation on Russians using jamming on anti ship missile exercises would be appreciated. I've never read about them use jamming equipment for anti ship trainings.
There isn't but during their ground exercices they always use jammers that affect even neighbour countries.
It's just that both missiles seem to miss the target which would be weired for such important missile that was in service since long time ago and tested many time. It shouldn't have problem hiting such target that is not even stealthy.
The way they miss makes me believe that jammers were used because they clearly have issues of distance measurment to the target. The second one doing better than the first one but still seems to miss and explode before touching it.
They don't launch real missiles that often so when they decide to test them they make many scenarios IMO. Trying to shot a target in a jamming environment must be one of them. The first video as you say is a vulkan and a moskit so they test a salvo attack composed of two differznt missiles to see how that would work and you can see the missiles are very well coordinated.
But no I have no proof about that just my opinion.